Q. Why do we need purgatory?
A. Sacred Scripture and Tradition repeatedly affirm that God’s ultimate intention is for us to become perfect as He is perfect (see Mt 5:48). Why?
Because God wants us to live forever in friendship with Him, and He Himself is completely holy — without sin or weakness of any kind. To see God face-to-face in heaven, and to know, love, and enjoy Him there fully forever, we must be like Him (see Heb 12:14; 1 Jn 3:2-3).
In fact, heaven simply wouldn’t be heaven unless those who lived there had been perfected. If we were to bring along with us all the sins and weaknesses we have in this life, heaven would be just as full of troubles as our life